- Acylboronates in polarity-reversed generation of acyl palladium(II) intermediates
-
We report a catalytic cross-coupling process between aryl (pseudo)halides and boron-based acyl anion equivalents. This mode of acylboronate reactivity represents polarity reversal, which is supported by the observation of tetracoordinated boronate and acyl palladium(II) species by 11B, 31P NMR, and mass spectrometry. A broad scope of aliphatic and aromatic acylboronates has been examined, as well as a variety of aryl (pseudo)halides.
- Trofimova, Alina,Holownia, Aleksandra,Tien, Chieh-Hung,?irvinskas, Martynas J.,Yudin, Andrei K.
-
supporting information
p. 3294 - 3299
(2021/05/07)
-
- Systematic Evaluation of 1,2-Migratory Aptitude in Alkylidene Carbenes
-
Alkylidene carbenes undergo rapid inter- and intramolecular reactions and rearrangements, including 1,2-migrations of β-substituents to generate alkynes. Their propensity for substituent migration exerts profound influence over the broader utility of alkylidene carbene intermediates, yet prior efforts to categorize 1,2-migratory aptitude in these elusive species have been hampered by disparate modes of carbene generation, ultrashort carbene lifetimes, mechanistic ambiguities, and the need to individually prepare a series of 13C-labeled precursors. Herein we report on the rearrangement of 13C-alkylidene carbenes generated in situ by the homologation of carbonyl compounds with [13C]-Li-TMS-diazomethane, an approach that obviates the need for isotopically labeled substrates and has expedited a systematic investigation (13C{1H} NMR, DLPNO-CCSD(T)) of migratory aptitudes in an unprecedented range of more than 30 alkylidene carbenes. Hammett analyses of the reactions of 26 differentially substituted benzophenones reveal several counterintuitive features of 1,2-migration in alkylidene carbenes that may prove of utility in the study and synthetic application of unsaturated carbenes more generally.
- Dale, Harvey J. A.,Nottingham, Chris,Poree, Carl,Lloyd-Jones, Guy C.
-
p. 2097 - 2107
(2021/02/01)
-
- Iridium-Catalysed Reductive Deoxygenation of Ketones with Formic Acid as Traceless Hydride Donor
-
An iridium-catalysed deoxygenation of ketones and aldehydes is achieved, with formic acid as hydride donor and water as co-solvent. At low catalyst loading, a number of 4-(N,N-disubstituted amino) aryl ketones are readily deoxygenated in excellent yields and chemoselectivity. Numerous functional groups, especially phenolic and alcoholic hydroxyls, secondary amine, carboxylic acid, and alkyl chloride, are well tolerable. Geminally dideuterated alkanes are obtained with up to 90% D incorporation, when DCO2D and D2O are used in place of their hydrogenative counterparts. The activating 4-(N,N-disubstituted amino)aryl groups have been demonstrated to undergo a variety of useful transformations. The deoxygenative deuterations have been used to prepare a deuterated drug molecule Chlorambucil-4,4-d2. (Figure presented.).
- Yang, Zhiheng,Zhu, Xueya,Yang, Shiyi,Cheng, Weiyan,Zhang, Xiaojian,Yang, Zhanhui
-
supporting information
p. 5496 - 5505
(2020/10/22)
-
- One-pot, modular approach to functionalized ketones via nucleophilic addition/Buchwald-Hartwig amination strategy
-
A general one-pot procedure for the 1,2-addition of organolithium reagents to amides followed by the Buchwald-Hartwig amination with in situ released lithium amides is presented. In this work amides are used as masked ketones, revealed by the addition of organolithium reagents which generates a lithium amide, suitable for subsequent Buchwald-Hartwig coupling in the presence of a palladium catalyst. This methodology allows for rapid, efficient and atom economic synthesis of aminoarylketones in good yields.
- De Jong, Jorn,Heijnen, Dorus,Helbert, Hugo,Feringa, Ben L.
-
supporting information
p. 2908 - 2911
(2019/03/17)
-
- Efficient Synthesis of Diaryl Ketones by Nickel-Catalyzed Negishi Cross-Coupling of Amides by Carbon–Nitrogen Bond Cleavage at Room Temperature Accelerated by a Solvent Effect
-
The first Negishi cross-coupling of amides for the synthesis of versatile diaryl ketones by selective C?N bond activation under exceedingly mild conditions is reported. The cross-coupling was accomplished with bench-stable, inexpensive precatalyst [Ni(PPh3)2Cl2] that shows high functional-group tolerance and enables the synthesis of highly functionalized diaryl ketone motifs. The coupling occurred with excellent chemoselectivity favoring the ketone (cf. biaryl) products. Notably, this process represents the mildest conditions for amide N?C bond activation accomplished to date (room temperature, 10 min). Considering the versatile role of polyfunctional biaryl ketone linchpins in modern organic synthesis, availability, and excellent functional-group tolerance of organozinc reagents, this strategy provides a new platform for amide N?C bond/organozinc cross-coupling under mild conditions.
- Shi, Shicheng,Szostak, Michal
-
p. 10420 - 10424
(2016/07/21)
-
- Synthesis of arylketones by ruthenium-catalyzed cross-coupling of aldehydes with arylboronic acids
-
The first ruthenium-catalyzed cross-coupling of aldehydes with arylboronic acids is reported. Various aliphatic and aromatic aldehydes are transformed to the corresponding arylketones. A total of 31 examples with moderate to excellent yields are presented, together with the results of an initial mechanistic investigation.
- Li, Hong,Xu, Yuan,Shi, Erbo,Wei, Wei,Suo, Xiangqiang,Wan, Xiaobing
-
supporting information; experimental part
p. 7880 - 7882
(2011/08/06)
-
- Unusual aminations with tetramethylguanidine
-
Heating activated halobenzenes with 1,1,3,3-tetramethylguanidine affords mixtures of dimethylaminobenzenes and 2-aryl-1,1,3,3-tetramethylguanidines.
- Gabbutt, Christopher D.,Heron, B. Mark,McCreary, Janice M.,Thomas, David A.
-
-
- OZONIZATION OF TRIPHENYLMETHANE DYES.
-
The reaction of Malachite Green (MG, 1a), a model compound of triphenylmethane dye, with ozone proceeded via two paths. The first path involved an ozone attack at the dimethylamino moiety to give a N-formylmethylamino derivative. The second path produced 4-(dimethylamino)benzophenone and p-(dimethylamino)phenol. Other ozonized products were also detected. A discussion is presented of the ozonization mechanism.
- Matsui,Nakabayashi,Shibata,Takase
-
p. 3312 - 3316
(2007/10/02)
-
- Stereochemical aspects of the metabolism of 5-(4'-fluorophenyl)-5-phenylhydantoin in the rat
-
Racemic 5-(4'-fluorophenyl)-5-phenylhydantoin was synthesized to examine its metabolism in rat. This compound differs from the antiepileptic agent 5,5-diphenylhydantoin in that the normal site of hydroxylation in 5,5-diphenylhydantoin is blocked on one of the phenyl groups by a fluorine atom. The 4'-fluoro analogue gives a major metabolite, which was isolated and identified as (R)-(-)-5-(4'-fluorophenyl)-5-(4'-hydroxyphenyl)hydantoin of 37% enantiomeric purity. The absolute configuration and enantiomeric purity of the metabolite were determined by chemical conversion to (S)-(-)-5-(4'-hydroxyphenyl)-5-phenylhydantoin. A second metabolite of the catechol type, possibly as a mixture of 5-(3',4'-dihydroxyphenyl)-5-(4'-fluorophenyl)hydantoin, and the corresponding O-3'-methyl derivative was detected by gas chromatography-mass spectrometry after methylation.
- Poupaert,Adline,Claesen,De Laey,Dumont
-
p. 1140 - 1142
(2007/10/06)
-